AAS 206th Meeting, 29 May - 2 June 2005
Session 10 Galaxies, Clusters and Large Scale Structure
Poster, Monday, 9:20am-6:30pm, Tuesday, 10:00am-7:00pm, May 30, 2005, Ballroom A

## [10.05] Faint U-band dropouts in the GOODS-CDFS field

Y. Wadadekar, S. Casertano (STScI)

We combine data from the extremely deep HST U (F300W) image obtained using WFPC2 as part of the parallel observations of the Hubble Ultra Deep Field campaign, with BVi images from the HST/GOODS survey to identify a sample of Lyman break galaxies in the redshift range 2.0 \leq z \leq 3.5.

We use recent stellar population synthesis models with a wide variety of ages, metallicities, dust contents and redshifts to model the colors of galaxies in our combination of WFPC2/ACS filters. We model the H~\scriptstyle\rm I\ cosmic opacity as a function of redshift including scattering in resonant lines of the Lyman series and Lyman continuum absorption. Using these models, we derive the color selection criteria that provide a clean selection of relatively unobscured, star forming galaxies in this redshift range.

The 10\sigma limiting magnitude measured over 0.2 arcsec2 is 27.5 magnitudes in the WFPC2/F300W image, about 0.5 magnitudes deeper than the F300W image in the HDF-N and 0.7 magnitudes deeper than that in the HDF-S. This extra depth relative to the HDFs allows us to probe the luminosity function about 0.5 magnitudes deeper than the depth accessible with the HDF data. This enables a better measurement of the luminosity function and star formation rate. Our sample of star-forming galaxies with 2.0 \leq z \leq 3.5 includes about 120 objects. We present a comparison of the number counts, morphology, luminosity function and star formation rate of our sample with the corresponding samples from the two HDFs.

Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.